Long-range interactions between self-assembled monolayers (SAMs) of semifluorinated alkanethiols have been studied by direct force measurements in water and aqueous NaCl solutions. SAMs prepared from three different thiols, with identical fluorinated head groups but varying hydrocarbon spacer length
Measurements of long-range attractive forces between hydrophobic surfaces and atomic force microscopy tips
โ Scribed by O. Teschke; E.F. de Souza
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 225 KB
- Volume
- 375
- Category
- Article
- ISSN
- 0009-2614
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โฆ Synopsis
We have measured the force acting on neutral tips as function of distance to hydrophobic surfaces in aqueous solutions. The unusually large magnitude of this force is attributed to an electrostatic response of the aqueous fluid structure (hydration layer). The exchange of a volume of this region with a dielectric permittivity int by the tip with a dielectric constant tip is responsible for the tip attraction when it is immersed in the hydration layer. Hydrophobic hydration layers, characterized by a variable dielectric permittivity profile, have measured widths of $4 and $8 nm for hydrophobic silicon and CTAB monolayer covering mica surfaces, respectively.
๐ SIMILAR VOLUMES
Interaction forces between a silica sphere and an a-alumina ments has been the surface force apparatus (2) in which substrate at various pH values were measured by atomic force forces between two macroscopic surfaces (usually mica) are microscopy (AFM). As expected, at pH values of 10.8 and 10.2 mea
III\_ MEASUREMENTS IN AIR ..\_\_\_.\_\_\_\_.\_\_\_\_\_\_.\_.\_~\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_~\_~\_\_\_\_\_\_\_\_\_\_66 IV\_ KEASUREMENTS IN ELECTROLYTE SOLUTIONS .\_.